toilet bowl flushing

How Does a Toilet Work?

Did you know that nearly 400 children under the age of 5 in India die from diarrhea linked to poor sanitation every day? Adequate sanitation is a major player in ensuring people live long and healthy lives and is especially important for the growth and wellness of children. The humble toilet is one of the main contributors to proper sanitation, but how does the modern flushable toilet work?

Main Parts of a Toilet

While toilet designs can vary from brand to brand, and even across types of toilets, they have the same main components – the cistern and the bowl.

The cistern is a tank of water that is emptied into the toilet bowl with the press of a button. Just by the force of gravity, waste is flushed from the toilet bowl and into your sewerage system. Sounds simple, right?

Toilets are relatively simple mechanisms, but there is a bit more going on than meets the eye. Inside the cistern, there are quite a few moving parts which go into flushing your toilet:

  • Inlet valve
  • Floating ball and rod
  • Piston
  • Siphon

All these parts work together by use of levers, pistons along with the force of gravity and mechanical action to flush waste into your sewer system.

How a Toilet Works

In your cistern, the inlet valve controls water entering the tank. When the tank is filled with water, the floating ball and rod block this valve so no water can enter the tank. When it is empty, the rod sits down the bottom of the tank and the valve is open to allow more water in.

As water enters the tank, the ball and rod float on top of the water and rise as more water enters. When the tank is full again, the rod blocks the inlet valve again. This mechanism allows the tank to automatically refill and also stops it from overflowing.

So if refilling the tank is automatic, how does it empty in the first place? The cistern is emptied when the flush button is pressed. This pulls a piston up and water floods to fill a siphon “U” tube. This tube carries liquid up from the tank, only for it to fall back down towards the toilet bowl.

This siphon action empties the tank quite quickly, and the float ball floats down to the bottom of the tank as the water is emptied.  The piston returns to block off the ‘U’ tube and the tank refills, ready for the next flush.

The water travels down a short pipe, around the rim and down the sides of the toilet bowl and finally goes out through the drainpipe, carrying the waste with it. Some clean water remains at the bottom of the toilet thanks to the ‘S’ bend. This prevents bad odours from your sewer system from escaping your toilet and permeating your bathroom. The ‘S’ bend also provides a second siphon action which helps to speed up the flushing process.

How has it Changed the World?

Toilets have made homes and cities much cleaner places to live. Combined with other plumbing features, toilets have helped provide proper sanitation to many parts of the world.

The toilet significantly reduces your exposure to human waste. This means you’re less at risk of developing diarrhea and other diseases linked to poor sanitation. Poor sanitation can also lead to:

  • Malnutrition
  • Low birth weight
  • Cognitive disabilities
  • Stunted growth
  • And much more

Poor sanitation even contributes to 2 out of 3 causes of preventable deaths in 2-5 year olds!

Having private toilet facilities also enables more young girls in developing countries to stay in school as many stop attending if these are not available.

For all the good things toilets have brought to the world, the taboo around loos is uncalled for. To talk more about toilet plumbing and ensuring yours is in working order, contact Metropolitan Plumbing.

Published: 6 Jul, 2020

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